Apparatus for preheating oil from oil cracking stills



April 124, 1932. {3, A OBUS 1,853,165

APPARATUS FOR PREHEATING OIL FROMOIL CRACKING STILLS Original Filed Sept. 29, 1921 INVENTOR. fl nk 4W.

A TTORNEYS.

A Patented Apr. 12, 1932 UNITED STATES PATENT OFFICE,

DAVID S. JACOB'U S, OF JERSEY CITY, NEW JERSEY, ASSIGNOR TO THE BAZBCOGK & WILGOX COMPANY, OF BAYONNE, NEW JERSEY, A CORPORATION OF NEW JERSEY APPARATUS FOR PIKE-HEATING OIL FROM OIL CBACMNG STILLS Application filed September 29, 1921, Serial No. 504,201. Renewed. March 10, 1931.

' My invention relates to oil heaters particularly when associated with stills for crack ing oil, together with methods of cracking oils in which preheating the oil is one of the steps and will be understood by. reference to the accompanying drawing illustrating one form of apparatus embodying my invention and by which my novel method may be carried out. I

In the drawing, a high pressure oil cracking still is shown, having oil heating tubes connecting upper andlower drums 11 and 12, the tubes 10 extending diagonally across a heating chamber 13 and the drums being located outside of that chamber. Above the roofof the heating chamber are located storage drums 14 and 15 connected by nipples 16, thelower drum 14 being connected to the upper drum 11 through pipes 17 and to the lower drum 12 through downcomer pipes 18.

A furnace 19 is arranged so that the gases therefrom will pass into the heating chamber 13, and, by reason of the presence of the bridge wall 20, will pass back and forth I across the tubes 10 to the gas outlet 21.

Extending diagonally across the lower front portion of the heating chamber 13 is a set of tubes 22 constituting the heating surface of the .oilpreheater. These tubes are connected to upper and lower drums 23 and 24, respectively, these drums being located outside of the heating chamber. A cross drum or header 25 extends above the drum 23 and is connected thereto by nipples 26. Similarly, a cross drum or header 27 is located beneath the drum 24 and is connected thereto by nipples 28.

At some convenient place, preferably at some distance from the still, is located a large storage tank 30 which is preferably insulated so as to retain the heat therein. Through the pipes 31 and 32, respectively, the headers 25 and 27 are connected to the upper and lower parts of the drum 30, a pump 33 preferably being interposed between the drum and the pipe 32. The drum 30 has an oil inlet pipe 34 and an oil outlet pipe 35 connected to' a .pump 36 from which leads a pipe 37 connected to the lower-drum 12 of the still.

The drum may be provided .with means for purifying the oil therein, one such means being illustrated as a plurality of sheets of metal 38, 38 suspended from rods 39 extendlngacross the upper part of the drum 30.

Preferably the furnace 19 is arranged so that both the tubes 22 and the tubes 10 are substantially protected from the direct radiant heat of the fire.

The arrangement comprising the heating tubes 22 and the drum 30 and the connections therebetween, constitutes an oil preheater for the oil cracking still. As illustrated, each still, if a plurality of them were in use, would have its own preheater as Wellas its individual drum 30. If desired, however, a common dllillm 30 may be provided for a plurality of sti s.

By providing the tubes 22 in a position Where they will be contacted by the gases from the furnace before these gases reach the tubes 10 of the still, the heat of'the gases is tem pered so that all of the tubes 10 are heated more uniformly than would be otherwise possible, and, at the same time, the heat taken from ,the gases is utilized in heating the oil in the tank 30.

In carrying out my method, the still is first charged with a quantity of oil, preferably until the level of the oil is somewhere midway of the drum 15. The drum 30 is also filled with oil which, of course, fills the heat ing tubes 22 and the connections between these tubes and the drum 30. Heat is then applied as from the furnace 1'9 and the hot gases gradually heat up the oil in the drum 30, the natural circulation through the tubes 22 tending to maintain a complete circulation through the preheater, such natural circulation being assisted, if preferred, by the pump 33. The drum 30 is provided with a vent 40 having a valve 41 controlled in any suitable manner, as by the adjustable weight 42, so that the pressure in the tank 30 may be held at any desired point, the vapors driven off from the heated oil being carried to any desired point for further use.

As the oil in the drum 30 is being heated, the oil' in the still will also. be heated, but since this still is designed for cracking oil, the pressure, as wellas the. temperature, is

. permitted to increase until the cracking point is reached. As the oil is cracked, the vapor will pass off through the vapor outlet 43 of the still, and the quantity of oil in the still will, therefore, constantly decrease in vol ume,and, at the same time, will increase in density. By my method, I may maintain the quantity of oil in the still substantially constant by starting the pump 36 and opening the valve 44: to permit some of the oil from the drum 30 to pass through the pipe 37 into the lower drum 12. In the drawings, the pipe 37 is shown as being connected di rectly to the lower drum 12. In place of this, the pipe 37 may lead to a dephlegmating tower, or other part of the system, and the oil from the pipe 37 made to enter the drum 12 along with the run-back from the dephleg mating tower.. The entrance of this fresh supply of heated oil into the still will not retard the cracking process to the extent it would be retarded by feeding cold oil, and, at the same time, will permit the cracking proc ess being continued for a much longer period than would otherwise be possible if nov addi tional fresh supply of oil were provided.

As a further step by which the cracking process ma be continued longer than has heretofore een possible, I may, after the oil in the still has reached a predetermined condition of concentration, remove from the still a quantity of this concentrated residual oil and then suppply to the still, oilfrom the drum 30 to make up for the amout that is withdrawn from the still. This fresh sup ply of uncracked oil will decrease the viscosity of theoil in the still, so that the cracking may be continued for a longer period than would be possible if this fresh supply were not provided.

Finally, when it is necessary to clean the still, it is refilled with heated oil from the tank 30 In this case, the cracking may be recommenced in a shorter time after such refilling than it would be if refilled with cold oil, because the preliminary heating of the oil has already been accomplished in the preheater, which delivers oil to the still at a temperature lower than that of the oil in the still. In order to remove impurities from the oil before passing it into the still, particularly such impurities as acid due to the sulphur, I provide the sheets of metal 38 along which the oil circulates in the preheater. This metal is corroded by the impurities that would cause corrosion in the still, so-that, before which may be used independently of the others if desired. By tempering the gases before thetubes 10 are contacted, the deposition of an excessive amount of carbon in such tubes,

by reason of high heating of the first of the tubes contacted, is avoided. Again, the tempering of the gases which strike the tubes 10 leads to being able to run the still with a thicker coating of carbon within the tubes before there isdanger of burning the tubes than would be the case with hotter gases. By providing a continuous fresh oil supply heated substantially to the cracking temperature the concentration or thickenin of the oil in the still is delayed, this thickening ultimately requiring the blowing down and clean ing of the still. By utilizing the step which I have described of-remo-ving some of this concentrated or thickened residue, and providing a make-up supply of thin, heated oil, the thickening or concentration of the oil in the still is also further delayed.

It will be understood that the device which I have illustrated is only one of many forms of arrangements by which my invention may be carried out, and that the construction may be varied within wide limits.

I claim 1. An oil cracking still, a furnace to heat the. still, an oil heater having its heating surface composed of tubes located between the furnace and the still and in the path of the heating gases, the gases flowing over the tubes of said heater before contacting with the heating surface of said still, a relatively large storage tank remote from and independent of the still, connections between the heater and the tank and arranged to permit the oil to circulate through the tank and the heater and a connection between the tank and the still.-

2. An oil cracking still, a furnace to heat the still, an oil heater having its heating surface composed of tubes located between the furnace and the still and in the path of the heating gases, the gases flowing over the tubes of said heater before contacting with the heating surface of said still, a relatively large storage tank remote from and independent of the still, connections between the heater and the tank, a pump to circulate the oil through the tank, connections and heater, anil1 a connection between the tank and the sti 3. An oil cracking still, a furnace to heat the still, an oil heater having its heating surface composed of tubes located between the furnace and the still and in the path of the heating gases, a relatively large storage tank remote from and independent of the still,

and arranged to permit the oil to circulate through the tank and the heater, a connection between the tank and the still, and means to regulate the pressure on the oil in-the tank.

4. An oil cracking still, a furnace to heat connections between the heater and the tank the still, an oil heater having its heating surface composed of tubes located between the furnace and the still and in the path of the heating gases, the ends of said tubes being connected to drums protected from the heat of the furnace, a relatively large storage tank remote from and independent of the still, connections between the heater and the tank and arranged to permit the oil to circulate through the tank and the heater and a connection between the tank and the still.

5. An oil cracking still, a furnace to heat the still, an oil heater having a relatively large storage drum for the heated oil, means to circulate the oil through the drum and past the heating surface of the heater, means in the drum to purify the heated oil, and means to force the heated and purified oil from the drum into the still.

6. An oil cracking still, a furnace to heat the still, an oil heater having a relatively large storage drum for the heated oil, means to circulate the oil through the drum and past the heating surface of the heater. sheet metal strips in the drum to purify the oil circulating therethrough, and means to force 7 the heated and purified oil into the still.

4 7 An oil cracking still having heating tubes, a furnace to heat the still and an oil heater comprising heating tubes, a tank and connections therebetween to permit a circulation of the oil in the tank and tubes as it is heated, the vapor space of the tank being unconnected with. the vapor snace of the still, and the oil heater heating tubes being located in the path of all of the heating gases from the furnace. whereby the gases are cooled before contacting with the still heating tubes.

8. An oil cracking still, a furnace to heat the still. means for creating a circulation of oil in said still, an oil heater having its heating surface composed of tubes located between the furnace and the still and in the path of the heating gases, the gases flowing over the tubes of said heater before contacting with the heating surface of said still, a relatively large storage tank remote from and independent of the still, connections between the heater and the tank and arranged to permit the oil to circulate through the tank and the heater and a connection between the tank and the still.

9. An oil cracking still, a furnace to heat the still, means for creating a circulation of oil in said still, an oil heater having its heating surface composed of tubes located between the furnace and the still and in the path of the heating gases, the gases flowing over the tubes of said heater before contacting with the heating surface of said still, a relatively large storage tank remote from and in dependent of the still, connections between the heater and the tank, a pump to circulate the oil through the tank, connections and tubes,

heater, and a connection between the tank 7 and the still.

10. An oil cracking still having heating a furnace to heat the still and an oil heater comprisin heating tubes, a tank and F connections there etween to permit a circulation of the oil in the tank and tubes as it is heated, the vapor space of the tank being unconnected with the vapor space of the still, and means for causing the gases from said furnace to-contact successivel the tubes of said oil heater and the tubes 0 said still.

DAVID S. JACOBUS. 

